The technical field of this invention is material analysis and, in particular the invention relates to the detection and quantification of analytes in materials by measuring reflectivity at multiple wavelengths.
Material analysis, especially the analysis of liquid materials for the presence of solutes, can be a tedious and complex task. In many instances it would be more desirable to be able to analyze materials quickly, easily, and non-invasively. One example of such an application is blood analysis.
Conventionally, blood is analyzed by withdrawing a sample from the body of a subject and examining it using one or more techniques such as immunoassays, activity assays, chromotographic assays, and spectrophotometric assays. These conventional methods all suffer from several common disadvantages. One such disadvantage is that it usually takes some time to perform tests on the sample, the length of time being dependent on the complexity of the test. This time delay between when the blood is drawn and when the analysis is completed provides a window during which the subject's blood content may have changed, leading to erroneous test results.
Additionally, situations arise when repeated or even continuous blood monitoring is desirable, for example when monitoring drug dosage changes or glucose level variations. In addition to the stale date problem discussed above, another disadvantage is that such repeated invasive blood sampling can cause discomfort to the subject being monitored. A further disadvantage to conventional blood testing techniques is that the people drawing and testing the blood sample are put at risk for exposure to infectious disease agents.
Accordingly, it is the object of the present invention to provide an analytic apparatus for non-invasively, quickly, and easily detecting and quantifying analytes in a material.
It is another object of this invention to provide an analytic apparatus particularly adapted for detecting and quantifying analytes in blood in such a way as to avoid the problems of stale test results, subject discomfort, and potential technician exposure to infectious agents.
It is also an object of the invention to provide a system that reduces the number of blood samples which must be drawn from patients who require repeated blood testing to evaluate such parameters as drug dose changes or glucose level variations, and to permit continuous analysis of blood within the circulatory system where desirable.